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* drivers/clk/clk-k210.c:717:6: warning: variable 'reg' set but not used
@ 2021-06-03  9:34 kernel test robot
  2021-06-03 10:03 ` Damien Le Moal
  0 siblings, 1 reply; 5+ messages in thread
From: kernel test robot @ 2021-06-03  9:34 UTC (permalink / raw)
  To: Damien Le Moal
  Cc: kbuild-all, clang-built-linux, linux-kernel, Palmer Dabbelt,
	Stephen Boyd

[-- Attachment #1: Type: text/plain, Size: 8286 bytes --]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   324c92e5e0ee0e993bdb106fac407846ed677f6b
commit: c6ca7616f7d5c2ce166280107ba74db1d528fcb7 clk: Add RISC-V Canaan Kendryte K210 clock driver
date:   3 months ago
config: riscv-randconfig-r033-20210603 (attached as .config)
compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project d8e0ae9a76a62bdc6117630d59bf9967ac9bb4ea)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install riscv cross compiling tool for clang build
        # apt-get install binutils-riscv64-linux-gnu
        # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c6ca7616f7d5c2ce166280107ba74db1d528fcb7
        git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
        git fetch --no-tags linus master
        git checkout c6ca7616f7d5c2ce166280107ba74db1d528fcb7
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=riscv 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   In file included from drivers/clk/clk-k210.c:8:
   In file included from include/linux/io.h:13:
   In file included from arch/riscv/include/asm/io.h:149:
   include/asm-generic/io.h:556:9: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           return inb(addr);
                  ^~~~~~~~~
   arch/riscv/include/asm/io.h:55:76: note: expanded from macro 'inb'
   #define inb(c)          ({ u8  __v; __io_pbr(); __v = readb_cpu((void*)(PCI_IOBASE + (c))); __io_par(__v); __v; })
                                                                           ~~~~~~~~~~ ^
   arch/riscv/include/asm/mmio.h:87:48: note: expanded from macro 'readb_cpu'
   #define readb_cpu(c)            ({ u8  __r = __raw_readb(c); __r; })
                                                            ^
   In file included from drivers/clk/clk-k210.c:8:
   In file included from include/linux/io.h:13:
   In file included from arch/riscv/include/asm/io.h:149:
   include/asm-generic/io.h:564:9: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           return inw(addr);
                  ^~~~~~~~~
   arch/riscv/include/asm/io.h:56:76: note: expanded from macro 'inw'
   #define inw(c)          ({ u16 __v; __io_pbr(); __v = readw_cpu((void*)(PCI_IOBASE + (c))); __io_par(__v); __v; })
                                                                           ~~~~~~~~~~ ^
   arch/riscv/include/asm/mmio.h:88:76: note: expanded from macro 'readw_cpu'
   #define readw_cpu(c)            ({ u16 __r = le16_to_cpu((__force __le16)__raw_readw(c)); __r; })
                                                                                        ^
   include/uapi/linux/byteorder/little_endian.h:36:51: note: expanded from macro '__le16_to_cpu'
   #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
                                                     ^
   In file included from drivers/clk/clk-k210.c:8:
   In file included from include/linux/io.h:13:
   In file included from arch/riscv/include/asm/io.h:149:
   include/asm-generic/io.h:572:9: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           return inl(addr);
                  ^~~~~~~~~
   arch/riscv/include/asm/io.h:57:76: note: expanded from macro 'inl'
   #define inl(c)          ({ u32 __v; __io_pbr(); __v = readl_cpu((void*)(PCI_IOBASE + (c))); __io_par(__v); __v; })
                                                                           ~~~~~~~~~~ ^
   arch/riscv/include/asm/mmio.h:89:76: note: expanded from macro 'readl_cpu'
   #define readl_cpu(c)            ({ u32 __r = le32_to_cpu((__force __le32)__raw_readl(c)); __r; })
                                                                                        ^
   include/uapi/linux/byteorder/little_endian.h:34:51: note: expanded from macro '__le32_to_cpu'
   #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
                                                     ^
   In file included from drivers/clk/clk-k210.c:8:
   In file included from include/linux/io.h:13:
   In file included from arch/riscv/include/asm/io.h:149:
   include/asm-generic/io.h:580:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           outb(value, addr);
           ^~~~~~~~~~~~~~~~~
   arch/riscv/include/asm/io.h:59:68: note: expanded from macro 'outb'
   #define outb(v,c)       ({ __io_pbw(); writeb_cpu((v),(void*)(PCI_IOBASE + (c))); __io_paw(); })
                                                                 ~~~~~~~~~~ ^
   arch/riscv/include/asm/mmio.h:91:52: note: expanded from macro 'writeb_cpu'
   #define writeb_cpu(v, c)        ((void)__raw_writeb((v), (c)))
                                                             ^
   In file included from drivers/clk/clk-k210.c:8:
   In file included from include/linux/io.h:13:
   In file included from arch/riscv/include/asm/io.h:149:
   include/asm-generic/io.h:588:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           outw(value, addr);
           ^~~~~~~~~~~~~~~~~
   arch/riscv/include/asm/io.h:60:68: note: expanded from macro 'outw'
   #define outw(v,c)       ({ __io_pbw(); writew_cpu((v),(void*)(PCI_IOBASE + (c))); __io_paw(); })
                                                                 ~~~~~~~~~~ ^
   arch/riscv/include/asm/mmio.h:92:76: note: expanded from macro 'writew_cpu'
   #define writew_cpu(v, c)        ((void)__raw_writew((__force u16)cpu_to_le16(v), (c)))
                                                                                     ^
   In file included from drivers/clk/clk-k210.c:8:
   In file included from include/linux/io.h:13:
   In file included from arch/riscv/include/asm/io.h:149:
   include/asm-generic/io.h:596:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           outl(value, addr);
           ^~~~~~~~~~~~~~~~~
   arch/riscv/include/asm/io.h:61:68: note: expanded from macro 'outl'
   #define outl(v,c)       ({ __io_pbw(); writel_cpu((v),(void*)(PCI_IOBASE + (c))); __io_paw(); })
                                                                 ~~~~~~~~~~ ^
   arch/riscv/include/asm/mmio.h:93:76: note: expanded from macro 'writel_cpu'
   #define writel_cpu(v, c)        ((void)__raw_writel((__force u32)cpu_to_le32(v), (c)))
                                                                                     ^
   In file included from drivers/clk/clk-k210.c:8:
   In file included from include/linux/io.h:13:
   In file included from arch/riscv/include/asm/io.h:149:
   include/asm-generic/io.h:1005:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           return (port > MMIO_UPPER_LIMIT) ? NULL : PCI_IOBASE + port;
                                                     ~~~~~~~~~~ ^
>> drivers/clk/clk-k210.c:717:6: warning: variable 'reg' set but not used [-Wunused-but-set-variable]
           u32 reg;
               ^
   8 warnings generated.


vim +/reg +717 drivers/clk/clk-k210.c

   710	
   711	static int k210_clk_set_parent(struct clk_hw *hw, u8 index)
   712	{
   713		struct k210_clk *kclk = to_k210_clk(hw);
   714		struct k210_sysclk *ksc = kclk->ksc;
   715		struct k210_clk_cfg *cfg = &k210_clk_cfgs[kclk->id];
   716		unsigned long flags;
 > 717		u32 reg;
   718	
   719		spin_lock_irqsave(&ksc->clk_lock, flags);
   720		reg = readl(ksc->regs + cfg->mux_reg);
   721		if (index)
   722			reg |= BIT(cfg->mux_bit);
   723		else
   724			reg &= ~BIT(cfg->mux_bit);
   725		spin_unlock_irqrestore(&ksc->clk_lock, flags);
   726	
   727		return 0;
   728	}
   729	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

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^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: drivers/clk/clk-k210.c:717:6: warning: variable 'reg' set but not used
  2021-06-03  9:34 drivers/clk/clk-k210.c:717:6: warning: variable 'reg' set but not used kernel test robot
@ 2021-06-03 10:03 ` Damien Le Moal
  2021-06-12  3:55   ` Palmer Dabbelt
  0 siblings, 1 reply; 5+ messages in thread
From: Damien Le Moal @ 2021-06-03 10:03 UTC (permalink / raw)
  To: Palmer Dabbelt, Stephen Boyd, linux-riscv; +Cc: linux-kernel

On 2021/06/03 18:35, kernel test robot wrote:
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head:   324c92e5e0ee0e993bdb106fac407846ed677f6b
> commit: c6ca7616f7d5c2ce166280107ba74db1d528fcb7 clk: Add RISC-V Canaan Kendryte K210 clock driver
> date:   3 months ago
> config: riscv-randconfig-r033-20210603 (attached as .config)
> compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project d8e0ae9a76a62bdc6117630d59bf9967ac9bb4ea)
> reproduce (this is a W=1 build):
>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         # install riscv cross compiling tool for clang build
>         # apt-get install binutils-riscv64-linux-gnu
>         # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c6ca7616f7d5c2ce166280107ba74db1d528fcb7
>         git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
>         git fetch --no-tags linus master
>         git checkout c6ca7616f7d5c2ce166280107ba74db1d528fcb7
>         # save the attached .config to linux build tree
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=riscv 
> 
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
> 
> All warnings (new ones prefixed by >>):
> 
>    In file included from drivers/clk/clk-k210.c:8:
>    In file included from include/linux/io.h:13:
>    In file included from arch/riscv/include/asm/io.h:149:
>    include/asm-generic/io.h:556:9: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            return inb(addr);
>                   ^~~~~~~~~
>    arch/riscv/include/asm/io.h:55:76: note: expanded from macro 'inb'
>    #define inb(c)          ({ u8  __v; __io_pbr(); __v = readb_cpu((void*)(PCI_IOBASE + (c))); __io_par(__v); __v; })
>                                                                            ~~~~~~~~~~ ^
>    arch/riscv/include/asm/mmio.h:87:48: note: expanded from macro 'readb_cpu'
>    #define readb_cpu(c)            ({ u8  __r = __raw_readb(c); __r; })
>                                                             ^
>    In file included from drivers/clk/clk-k210.c:8:
>    In file included from include/linux/io.h:13:
>    In file included from arch/riscv/include/asm/io.h:149:
>    include/asm-generic/io.h:564:9: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            return inw(addr);
>                   ^~~~~~~~~
>    arch/riscv/include/asm/io.h:56:76: note: expanded from macro 'inw'
>    #define inw(c)          ({ u16 __v; __io_pbr(); __v = readw_cpu((void*)(PCI_IOBASE + (c))); __io_par(__v); __v; })
>                                                                            ~~~~~~~~~~ ^
>    arch/riscv/include/asm/mmio.h:88:76: note: expanded from macro 'readw_cpu'
>    #define readw_cpu(c)            ({ u16 __r = le16_to_cpu((__force __le16)__raw_readw(c)); __r; })
>                                                                                         ^
>    include/uapi/linux/byteorder/little_endian.h:36:51: note: expanded from macro '__le16_to_cpu'
>    #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
>                                                      ^
>    In file included from drivers/clk/clk-k210.c:8:
>    In file included from include/linux/io.h:13:
>    In file included from arch/riscv/include/asm/io.h:149:
>    include/asm-generic/io.h:572:9: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            return inl(addr);
>                   ^~~~~~~~~
>    arch/riscv/include/asm/io.h:57:76: note: expanded from macro 'inl'
>    #define inl(c)          ({ u32 __v; __io_pbr(); __v = readl_cpu((void*)(PCI_IOBASE + (c))); __io_par(__v); __v; })
>                                                                            ~~~~~~~~~~ ^
>    arch/riscv/include/asm/mmio.h:89:76: note: expanded from macro 'readl_cpu'
>    #define readl_cpu(c)            ({ u32 __r = le32_to_cpu((__force __le32)__raw_readl(c)); __r; })
>                                                                                         ^
>    include/uapi/linux/byteorder/little_endian.h:34:51: note: expanded from macro '__le32_to_cpu'
>    #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
>                                                      ^
>    In file included from drivers/clk/clk-k210.c:8:
>    In file included from include/linux/io.h:13:
>    In file included from arch/riscv/include/asm/io.h:149:
>    include/asm-generic/io.h:580:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            outb(value, addr);
>            ^~~~~~~~~~~~~~~~~
>    arch/riscv/include/asm/io.h:59:68: note: expanded from macro 'outb'
>    #define outb(v,c)       ({ __io_pbw(); writeb_cpu((v),(void*)(PCI_IOBASE + (c))); __io_paw(); })
>                                                                  ~~~~~~~~~~ ^
>    arch/riscv/include/asm/mmio.h:91:52: note: expanded from macro 'writeb_cpu'
>    #define writeb_cpu(v, c)        ((void)__raw_writeb((v), (c)))
>                                                              ^
>    In file included from drivers/clk/clk-k210.c:8:
>    In file included from include/linux/io.h:13:
>    In file included from arch/riscv/include/asm/io.h:149:
>    include/asm-generic/io.h:588:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            outw(value, addr);
>            ^~~~~~~~~~~~~~~~~
>    arch/riscv/include/asm/io.h:60:68: note: expanded from macro 'outw'
>    #define outw(v,c)       ({ __io_pbw(); writew_cpu((v),(void*)(PCI_IOBASE + (c))); __io_paw(); })
>                                                                  ~~~~~~~~~~ ^
>    arch/riscv/include/asm/mmio.h:92:76: note: expanded from macro 'writew_cpu'
>    #define writew_cpu(v, c)        ((void)__raw_writew((__force u16)cpu_to_le16(v), (c)))
>                                                                                      ^
>    In file included from drivers/clk/clk-k210.c:8:
>    In file included from include/linux/io.h:13:
>    In file included from arch/riscv/include/asm/io.h:149:
>    include/asm-generic/io.h:596:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            outl(value, addr);
>            ^~~~~~~~~~~~~~~~~
>    arch/riscv/include/asm/io.h:61:68: note: expanded from macro 'outl'
>    #define outl(v,c)       ({ __io_pbw(); writel_cpu((v),(void*)(PCI_IOBASE + (c))); __io_paw(); })
>                                                                  ~~~~~~~~~~ ^
>    arch/riscv/include/asm/mmio.h:93:76: note: expanded from macro 'writel_cpu'
>    #define writel_cpu(v, c)        ((void)__raw_writel((__force u32)cpu_to_le32(v), (c)))
>                                                                                      ^
>    In file included from drivers/clk/clk-k210.c:8:
>    In file included from include/linux/io.h:13:
>    In file included from arch/riscv/include/asm/io.h:149:
>    include/asm-generic/io.h:1005:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            return (port > MMIO_UPPER_LIMIT) ? NULL : PCI_IOBASE + port;
>                                                      ~~~~~~~~~~ ^
>>> drivers/clk/clk-k210.c:717:6: warning: variable 'reg' set but not used [-Wunused-but-set-variable]
>            u32 reg;
>                ^
>    8 warnings generated.
> 
> 
> vim +/reg +717 drivers/clk/clk-k210.c
> 
>    710	
>    711	static int k210_clk_set_parent(struct clk_hw *hw, u8 index)
>    712	{
>    713		struct k210_clk *kclk = to_k210_clk(hw);
>    714		struct k210_sysclk *ksc = kclk->ksc;
>    715		struct k210_clk_cfg *cfg = &k210_clk_cfgs[kclk->id];
>    716		unsigned long flags;
>  > 717		u32 reg;

Palmer,

I do not think this driver is the real cause of this error. Did something change
recently with risc-v mmio readl()/writel() ?

>    718	
>    719		spin_lock_irqsave(&ksc->clk_lock, flags);
>    720		reg = readl(ksc->regs + cfg->mux_reg);
>    721		if (index)
>    722			reg |= BIT(cfg->mux_bit);
>    723		else
>    724			reg &= ~BIT(cfg->mux_bit);
>    725		spin_unlock_irqrestore(&ksc->clk_lock, flags);
>    726	
>    727		return 0;
>    728	}
>    729	
> 
> ---
> 0-DAY CI Kernel Test Service, Intel Corporation
> https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
> 


-- 
Damien Le Moal
Western Digital Research

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: drivers/clk/clk-k210.c:717:6: warning: variable 'reg' set but not used
  2021-06-03 10:03 ` Damien Le Moal
@ 2021-06-12  3:55   ` Palmer Dabbelt
  2021-06-12 13:18     ` Jisheng Zhang
  2021-06-14  2:08     ` Damien Le Moal
  0 siblings, 2 replies; 5+ messages in thread
From: Palmer Dabbelt @ 2021-06-12  3:55 UTC (permalink / raw)
  To: Damien Le Moal; +Cc: sboyd, linux-riscv, linux-kernel

On Thu, 03 Jun 2021 03:03:14 PDT (-0700), Damien Le Moal wrote:
>> On 2021/06/03 18:35, kernel test robot wrote:
>> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
>> head:   324c92e5e0ee0e993bdb106fac407846ed677f6b
>> commit: c6ca7616f7d5c2ce166280107ba74db1d528fcb7 clk: Add RISC-V Canaan Kendryte K210 clock driver
>> date:   3 months ago
>> config: riscv-randconfig-r033-20210603 (attached as .config)
>> compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project d8e0ae9a76a62bdc6117630d59bf9967ac9bb4ea)
>> reproduce (this is a W=1 build):
>>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>>         chmod +x ~/bin/make.cross
>>         # install riscv cross compiling tool for clang build
>>         # apt-get install binutils-riscv64-linux-gnu
>>         # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c6ca7616f7d5c2ce166280107ba74db1d528fcb7
>>         git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
>>         git fetch --no-tags linus master
>>         git checkout c6ca7616f7d5c2ce166280107ba74db1d528fcb7
>>         # save the attached .config to linux build tree
>>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=riscv 
>> 
>> If you fix the issue, kindly add following tag as appropriate
>> Reported-by: kernel test robot <lkp@intel.com>
>> 
>> All warnings (new ones prefixed by >>):
>> 
>>    In file included from drivers/clk/clk-k210.c:8:
>>    In file included from include/linux/io.h:13:
>>    In file included from arch/riscv/include/asm/io.h:149:
>>    include/asm-generic/io.h:556:9: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>>            return inb(addr);
>>                   ^~~~~~~~~
>>    arch/riscv/include/asm/io.h:55:76: note: expanded from macro 'inb'
>>    #define inb(c)          ({ u8  __v; __io_pbr(); __v = readb_cpu((void*)(PCI_IOBASE + (c))); __io_par(__v); __v; })
>>                                                                            ~~~~~~~~~~ ^
>>    arch/riscv/include/asm/mmio.h:87:48: note: expanded from macro 'readb_cpu'
>>    #define readb_cpu(c)            ({ u8  __r = __raw_readb(c); __r; })
>>                                                             ^
>>    In file included from drivers/clk/clk-k210.c:8:
>>    In file included from include/linux/io.h:13:
>>    In file included from arch/riscv/include/asm/io.h:149:
>>    include/asm-generic/io.h:564:9: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>>            return inw(addr);
>>                   ^~~~~~~~~
>>    arch/riscv/include/asm/io.h:56:76: note: expanded from macro 'inw'
>>    #define inw(c)          ({ u16 __v; __io_pbr(); __v = readw_cpu((void*)(PCI_IOBASE + (c))); __io_par(__v); __v; })
>>                                                                            ~~~~~~~~~~ ^
>>    arch/riscv/include/asm/mmio.h:88:76: note: expanded from macro 'readw_cpu'
>>    #define readw_cpu(c)            ({ u16 __r = le16_to_cpu((__force __le16)__raw_readw(c)); __r; })
>>                                                                                         ^
>>    include/uapi/linux/byteorder/little_endian.h:36:51: note: expanded from macro '__le16_to_cpu'
>>    #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
>>                                                      ^
>>    In file included from drivers/clk/clk-k210.c:8:
>>    In file included from include/linux/io.h:13:
>>    In file included from arch/riscv/include/asm/io.h:149:
>>    include/asm-generic/io.h:572:9: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>>            return inl(addr);
>>                   ^~~~~~~~~
>>    arch/riscv/include/asm/io.h:57:76: note: expanded from macro 'inl'
>>    #define inl(c)          ({ u32 __v; __io_pbr(); __v = readl_cpu((void*)(PCI_IOBASE + (c))); __io_par(__v); __v; })
>>                                                                            ~~~~~~~~~~ ^
>>    arch/riscv/include/asm/mmio.h:89:76: note: expanded from macro 'readl_cpu'
>>    #define readl_cpu(c)            ({ u32 __r = le32_to_cpu((__force __le32)__raw_readl(c)); __r; })
>>                                                                                         ^
>>    include/uapi/linux/byteorder/little_endian.h:34:51: note: expanded from macro '__le32_to_cpu'
>>    #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
>>                                                      ^
>>    In file included from drivers/clk/clk-k210.c:8:
>>    In file included from include/linux/io.h:13:
>>    In file included from arch/riscv/include/asm/io.h:149:
>>    include/asm-generic/io.h:580:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>>            outb(value, addr);
>>            ^~~~~~~~~~~~~~~~~
>>    arch/riscv/include/asm/io.h:59:68: note: expanded from macro 'outb'
>>    #define outb(v,c)       ({ __io_pbw(); writeb_cpu((v),(void*)(PCI_IOBASE + (c))); __io_paw(); })
>>                                                                  ~~~~~~~~~~ ^
>>    arch/riscv/include/asm/mmio.h:91:52: note: expanded from macro 'writeb_cpu'
>>    #define writeb_cpu(v, c)        ((void)__raw_writeb((v), (c)))
>>                                                              ^
>>    In file included from drivers/clk/clk-k210.c:8:
>>    In file included from include/linux/io.h:13:
>>    In file included from arch/riscv/include/asm/io.h:149:
>>    include/asm-generic/io.h:588:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>>            outw(value, addr);
>>            ^~~~~~~~~~~~~~~~~
>>    arch/riscv/include/asm/io.h:60:68: note: expanded from macro 'outw'
>>    #define outw(v,c)       ({ __io_pbw(); writew_cpu((v),(void*)(PCI_IOBASE + (c))); __io_paw(); })
>>                                                                  ~~~~~~~~~~ ^
>>    arch/riscv/include/asm/mmio.h:92:76: note: expanded from macro 'writew_cpu'
>>    #define writew_cpu(v, c)        ((void)__raw_writew((__force u16)cpu_to_le16(v), (c)))
>>                                                                                      ^
>>    In file included from drivers/clk/clk-k210.c:8:
>>    In file included from include/linux/io.h:13:
>>    In file included from arch/riscv/include/asm/io.h:149:
>>    include/asm-generic/io.h:596:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>>            outl(value, addr);
>>            ^~~~~~~~~~~~~~~~~
>>    arch/riscv/include/asm/io.h:61:68: note: expanded from macro 'outl'
>>    #define outl(v,c)       ({ __io_pbw(); writel_cpu((v),(void*)(PCI_IOBASE + (c))); __io_paw(); })
>>                                                                  ~~~~~~~~~~ ^
>>    arch/riscv/include/asm/mmio.h:93:76: note: expanded from macro 'writel_cpu'
>>    #define writel_cpu(v, c)        ((void)__raw_writel((__force u32)cpu_to_le32(v), (c)))
>>                                                                                      ^
>>    In file included from drivers/clk/clk-k210.c:8:
>>    In file included from include/linux/io.h:13:
>>    In file included from arch/riscv/include/asm/io.h:149:
>>    include/asm-generic/io.h:1005:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>>            return (port > MMIO_UPPER_LIMIT) ? NULL : PCI_IOBASE + port;
>>                                                      ~~~~~~~~~~ ^
>>>> drivers/clk/clk-k210.c:717:6: warning: variable 'reg' set but not used [-Wunused-but-set-variable]
>>            u32 reg;
>>                ^
>>    8 warnings generated.
>> 
>> 
>> vim +/reg +717 drivers/clk/clk-k210.c
>> 
>>    710	
>>    711	static int k210_clk_set_parent(struct clk_hw *hw, u8 index)
>>    712	{
>>    713		struct k210_clk *kclk = to_k210_clk(hw);
>>    714		struct k210_sysclk *ksc = kclk->ksc;
>>    715		struct k210_clk_cfg *cfg = &k210_clk_cfgs[kclk->id];
>>    716		unsigned long flags;
>>  > 717		u32 reg;
>
> Palmer,
>
> I do not think this driver is the real cause of this error. Did something change
> recently with risc-v mmio readl()/writel() ?

I have no idea what's going on here.  When I try to re-build that config 
I don't get any warnings or errors.  That said...

>>    718	
>>    719		spin_lock_irqsave(&ksc->clk_lock, flags);
>>    720		reg = readl(ksc->regs + cfg->mux_reg);
>>    721		if (index)
>>    722			reg |= BIT(cfg->mux_bit);
>>    723		else
>>    724			reg &= ~BIT(cfg->mux_bit);
>>    725		spin_unlock_irqrestore(&ksc->clk_lock, flags);

Isn't reg unused here?  That's one of the warnings.

The void* casting has been there for a while and looks like a real bug, 
but asm-generic adopted our {in,out}{bwlq} implementation so I'm just 
going to toss ours.  I'm not quite sure why the generic ones aren't 
doing arithmetic on void*, but I'm not getting warnings.

>>    726	
>>    727		return 0;
>>    728	}
>>    729	
>> 
>> ---
>> 0-DAY CI Kernel Test Service, Intel Corporation
>> https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
>> 
>
>
>-- 
>Damien Le Moal
>Western Digital Research
>

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: drivers/clk/clk-k210.c:717:6: warning: variable 'reg' set but not used
  2021-06-12  3:55   ` Palmer Dabbelt
@ 2021-06-12 13:18     ` Jisheng Zhang
  2021-06-14  2:08     ` Damien Le Moal
  1 sibling, 0 replies; 5+ messages in thread
From: Jisheng Zhang @ 2021-06-12 13:18 UTC (permalink / raw)
  To: Palmer Dabbelt, Christoph Hellwig
  Cc: Damien Le Moal, sboyd, linux-riscv, linux-kernel

On Fri, 11 Jun 2021 20:55:41 -0700 (PDT)
Palmer Dabbelt <palmerdabbelt@google.com> wrote:

> On Thu, 03 Jun 2021 03:03:14 PDT (-0700), Damien Le Moal wrote:
> >> On 2021/06/03 18:35, kernel test robot wrote:
> >> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> >> head:   324c92e5e0ee0e993bdb106fac407846ed677f6b
> >> commit: c6ca7616f7d5c2ce166280107ba74db1d528fcb7 clk: Add RISC-V Canaan Kendryte K210 clock driver
> >> date:   3 months ago
> >> config: riscv-randconfig-r033-20210603 (attached as .config)
> >> compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project d8e0ae9a76a62bdc6117630d59bf9967ac9bb4ea)
> >> reproduce (this is a W=1 build):
> >>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> >>         chmod +x ~/bin/make.cross
> >>         # install riscv cross compiling tool for clang build
> >>         # apt-get install binutils-riscv64-linux-gnu
> >>         # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c6ca7616f7d5c2ce166280107ba74db1d528fcb7
> >>         git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> >>         git fetch --no-tags linus master
> >>         git checkout c6ca7616f7d5c2ce166280107ba74db1d528fcb7
> >>         # save the attached .config to linux build tree
> >>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=riscv 
> >> 
> >> If you fix the issue, kindly add following tag as appropriate
> >> Reported-by: kernel test robot <lkp@intel.com>
> >> 
> >> All warnings (new ones prefixed by >>):
> >> 
> >>    In file included from drivers/clk/clk-k210.c:8:
> >>    In file included from include/linux/io.h:13:
> >>    In file included from arch/riscv/include/asm/io.h:149:
> >>    include/asm-generic/io.h:556:9: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
> >>            return inb(addr);
> >>                   ^~~~~~~~~
> >>    arch/riscv/include/asm/io.h:55:76: note: expanded from macro 'inb'
> >>    #define inb(c)          ({ u8  __v; __io_pbr(); __v = readb_cpu((void*)(PCI_IOBASE + (c))); __io_par(__v); __v; })
> >>                                                                            ~~~~~~~~~~ ^
> >>    arch/riscv/include/asm/mmio.h:87:48: note: expanded from macro 'readb_cpu'
> >>    #define readb_cpu(c)            ({ u8  __r = __raw_readb(c); __r; })
> >>                                                             ^
> >>    In file included from drivers/clk/clk-k210.c:8:
> >>    In file included from include/linux/io.h:13:
> >>    In file included from arch/riscv/include/asm/io.h:149:
> >>    include/asm-generic/io.h:564:9: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
> >>            return inw(addr);
> >>                   ^~~~~~~~~
> >>    arch/riscv/include/asm/io.h:56:76: note: expanded from macro 'inw'
> >>    #define inw(c)          ({ u16 __v; __io_pbr(); __v = readw_cpu((void*)(PCI_IOBASE + (c))); __io_par(__v); __v; })
> >>                                                                            ~~~~~~~~~~ ^
> >>    arch/riscv/include/asm/mmio.h:88:76: note: expanded from macro 'readw_cpu'
> >>    #define readw_cpu(c)            ({ u16 __r = le16_to_cpu((__force __le16)__raw_readw(c)); __r; })
> >>                                                                                         ^
> >>    include/uapi/linux/byteorder/little_endian.h:36:51: note: expanded from macro '__le16_to_cpu'
> >>    #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
> >>                                                      ^
> >>    In file included from drivers/clk/clk-k210.c:8:
> >>    In file included from include/linux/io.h:13:
> >>    In file included from arch/riscv/include/asm/io.h:149:
> >>    include/asm-generic/io.h:572:9: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
> >>            return inl(addr);
> >>                   ^~~~~~~~~
> >>    arch/riscv/include/asm/io.h:57:76: note: expanded from macro 'inl'
> >>    #define inl(c)          ({ u32 __v; __io_pbr(); __v = readl_cpu((void*)(PCI_IOBASE + (c))); __io_par(__v); __v; })
> >>                                                                            ~~~~~~~~~~ ^
> >>    arch/riscv/include/asm/mmio.h:89:76: note: expanded from macro 'readl_cpu'
> >>    #define readl_cpu(c)            ({ u32 __r = le32_to_cpu((__force __le32)__raw_readl(c)); __r; })
> >>                                                                                         ^
> >>    include/uapi/linux/byteorder/little_endian.h:34:51: note: expanded from macro '__le32_to_cpu'
> >>    #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
> >>                                                      ^
> >>    In file included from drivers/clk/clk-k210.c:8:
> >>    In file included from include/linux/io.h:13:
> >>    In file included from arch/riscv/include/asm/io.h:149:
> >>    include/asm-generic/io.h:580:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
> >>            outb(value, addr);
> >>            ^~~~~~~~~~~~~~~~~
> >>    arch/riscv/include/asm/io.h:59:68: note: expanded from macro 'outb'
> >>    #define outb(v,c)       ({ __io_pbw(); writeb_cpu((v),(void*)(PCI_IOBASE + (c))); __io_paw(); })
> >>                                                                  ~~~~~~~~~~ ^
> >>    arch/riscv/include/asm/mmio.h:91:52: note: expanded from macro 'writeb_cpu'
> >>    #define writeb_cpu(v, c)        ((void)__raw_writeb((v), (c)))
> >>                                                              ^
> >>    In file included from drivers/clk/clk-k210.c:8:
> >>    In file included from include/linux/io.h:13:
> >>    In file included from arch/riscv/include/asm/io.h:149:
> >>    include/asm-generic/io.h:588:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
> >>            outw(value, addr);
> >>            ^~~~~~~~~~~~~~~~~
> >>    arch/riscv/include/asm/io.h:60:68: note: expanded from macro 'outw'
> >>    #define outw(v,c)       ({ __io_pbw(); writew_cpu((v),(void*)(PCI_IOBASE + (c))); __io_paw(); })
> >>                                                                  ~~~~~~~~~~ ^
> >>    arch/riscv/include/asm/mmio.h:92:76: note: expanded from macro 'writew_cpu'
> >>    #define writew_cpu(v, c)        ((void)__raw_writew((__force u16)cpu_to_le16(v), (c)))
> >>                                                                                      ^
> >>    In file included from drivers/clk/clk-k210.c:8:
> >>    In file included from include/linux/io.h:13:
> >>    In file included from arch/riscv/include/asm/io.h:149:
> >>    include/asm-generic/io.h:596:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
> >>            outl(value, addr);
> >>            ^~~~~~~~~~~~~~~~~
> >>    arch/riscv/include/asm/io.h:61:68: note: expanded from macro 'outl'
> >>    #define outl(v,c)       ({ __io_pbw(); writel_cpu((v),(void*)(PCI_IOBASE + (c))); __io_paw(); })
> >>                                                                  ~~~~~~~~~~ ^
> >>    arch/riscv/include/asm/mmio.h:93:76: note: expanded from macro 'writel_cpu'
> >>    #define writel_cpu(v, c)        ((void)__raw_writel((__force u32)cpu_to_le32(v), (c)))
> >>                                                                                      ^
> >>    In file included from drivers/clk/clk-k210.c:8:
> >>    In file included from include/linux/io.h:13:
> >>    In file included from arch/riscv/include/asm/io.h:149:
> >>    include/asm-generic/io.h:1005:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
> >>            return (port > MMIO_UPPER_LIMIT) ? NULL : PCI_IOBASE + port;

+ Christoph

This warning can only be reproduced with clang + W=1
The problem is that PCI_IOBASE isn't defined for NOMMU, so clang complains
null pointer arithmetic.


> >>                                                      ~~~~~~~~~~ ^  
> >>>> drivers/clk/clk-k210.c:717:6: warning: variable 'reg' set but not used [-Wunused-but-set-variable]  
> >>            u32 reg;
> >>                ^
> >>    8 warnings generated.

This warning can't be reproduced even with clang + W=1

> >> 
> >> 
> >> vim +/reg +717 drivers/clk/clk-k210.c
> >> 
> >>    710	
> >>    711	static int k210_clk_set_parent(struct clk_hw *hw, u8 index)
> >>    712	{
> >>    713		struct k210_clk *kclk = to_k210_clk(hw);
> >>    714		struct k210_sysclk *ksc = kclk->ksc;
> >>    715		struct k210_clk_cfg *cfg = &k210_clk_cfgs[kclk->id];
> >>    716		unsigned long flags;  
> >>  > 717		u32 reg;  
> >
> > Palmer,
> >
> > I do not think this driver is the real cause of this error. Did something change
> > recently with risc-v mmio readl()/writel() ?  
> 
> I have no idea what's going on here.  When I try to re-build that config 
> I don't get any warnings or errors.  That said...
> 
> >>    718	
> >>    719		spin_lock_irqsave(&ksc->clk_lock, flags);
> >>    720		reg = readl(ksc->regs + cfg->mux_reg);
> >>    721		if (index)
> >>    722			reg |= BIT(cfg->mux_bit);
> >>    723		else
> >>    724			reg &= ~BIT(cfg->mux_bit);
> >>    725		spin_unlock_irqrestore(&ksc->clk_lock, flags);  
> 
> Isn't reg unused here?  That's one of the warnings.
> 
> The void* casting has been there for a while and looks like a real bug, 
> but asm-generic adopted our {in,out}{bwlq} implementation so I'm just 
> going to toss ours.  I'm not quite sure why the generic ones aren't 
> doing arithmetic on void*, but I'm not getting warnings.
> 
> >>    726	
> >>    727		return 0;
> >>    728	}
> >>    729	
> >> 
> >> ---
> >> 0-DAY CI Kernel Test Service, Intel Corporation
> >> https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
> >>   
> >
> >
> >-- 
> >Damien Le Moal
> >Western Digital Research
> >  
> 
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv



^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: drivers/clk/clk-k210.c:717:6: warning: variable 'reg' set but not used
  2021-06-12  3:55   ` Palmer Dabbelt
  2021-06-12 13:18     ` Jisheng Zhang
@ 2021-06-14  2:08     ` Damien Le Moal
  1 sibling, 0 replies; 5+ messages in thread
From: Damien Le Moal @ 2021-06-14  2:08 UTC (permalink / raw)
  To: Palmer Dabbelt; +Cc: sboyd, linux-riscv, linux-kernel

On 2021/06/12 12:55, Palmer Dabbelt wrote:
> On Thu, 03 Jun 2021 03:03:14 PDT (-0700), Damien Le Moal wrote:
>>> On 2021/06/03 18:35, kernel test robot wrote:
>>> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
>>> head:   324c92e5e0ee0e993bdb106fac407846ed677f6b
>>> commit: c6ca7616f7d5c2ce166280107ba74db1d528fcb7 clk: Add RISC-V Canaan Kendryte K210 clock driver
>>> date:   3 months ago
>>> config: riscv-randconfig-r033-20210603 (attached as .config)
>>> compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project d8e0ae9a76a62bdc6117630d59bf9967ac9bb4ea)
>>> reproduce (this is a W=1 build):
>>>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>>>         chmod +x ~/bin/make.cross
>>>         # install riscv cross compiling tool for clang build
>>>         # apt-get install binutils-riscv64-linux-gnu
>>>         # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c6ca7616f7d5c2ce166280107ba74db1d528fcb7
>>>         git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
>>>         git fetch --no-tags linus master
>>>         git checkout c6ca7616f7d5c2ce166280107ba74db1d528fcb7
>>>         # save the attached .config to linux build tree
>>>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=riscv 
>>>
>>> If you fix the issue, kindly add following tag as appropriate
>>> Reported-by: kernel test robot <lkp@intel.com>
>>>
>>> All warnings (new ones prefixed by >>):
>>>
>>>    In file included from drivers/clk/clk-k210.c:8:
>>>    In file included from include/linux/io.h:13:
>>>    In file included from arch/riscv/include/asm/io.h:149:
>>>    include/asm-generic/io.h:556:9: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>>>            return inb(addr);
>>>                   ^~~~~~~~~
>>>    arch/riscv/include/asm/io.h:55:76: note: expanded from macro 'inb'
>>>    #define inb(c)          ({ u8  __v; __io_pbr(); __v = readb_cpu((void*)(PCI_IOBASE + (c))); __io_par(__v); __v; })
>>>                                                                            ~~~~~~~~~~ ^
>>>    arch/riscv/include/asm/mmio.h:87:48: note: expanded from macro 'readb_cpu'
>>>    #define readb_cpu(c)            ({ u8  __r = __raw_readb(c); __r; })
>>>                                                             ^
>>>    In file included from drivers/clk/clk-k210.c:8:
>>>    In file included from include/linux/io.h:13:
>>>    In file included from arch/riscv/include/asm/io.h:149:
>>>    include/asm-generic/io.h:564:9: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>>>            return inw(addr);
>>>                   ^~~~~~~~~
>>>    arch/riscv/include/asm/io.h:56:76: note: expanded from macro 'inw'
>>>    #define inw(c)          ({ u16 __v; __io_pbr(); __v = readw_cpu((void*)(PCI_IOBASE + (c))); __io_par(__v); __v; })
>>>                                                                            ~~~~~~~~~~ ^
>>>    arch/riscv/include/asm/mmio.h:88:76: note: expanded from macro 'readw_cpu'
>>>    #define readw_cpu(c)            ({ u16 __r = le16_to_cpu((__force __le16)__raw_readw(c)); __r; })
>>>                                                                                         ^
>>>    include/uapi/linux/byteorder/little_endian.h:36:51: note: expanded from macro '__le16_to_cpu'
>>>    #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
>>>                                                      ^
>>>    In file included from drivers/clk/clk-k210.c:8:
>>>    In file included from include/linux/io.h:13:
>>>    In file included from arch/riscv/include/asm/io.h:149:
>>>    include/asm-generic/io.h:572:9: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>>>            return inl(addr);
>>>                   ^~~~~~~~~
>>>    arch/riscv/include/asm/io.h:57:76: note: expanded from macro 'inl'
>>>    #define inl(c)          ({ u32 __v; __io_pbr(); __v = readl_cpu((void*)(PCI_IOBASE + (c))); __io_par(__v); __v; })
>>>                                                                            ~~~~~~~~~~ ^
>>>    arch/riscv/include/asm/mmio.h:89:76: note: expanded from macro 'readl_cpu'
>>>    #define readl_cpu(c)            ({ u32 __r = le32_to_cpu((__force __le32)__raw_readl(c)); __r; })
>>>                                                                                         ^
>>>    include/uapi/linux/byteorder/little_endian.h:34:51: note: expanded from macro '__le32_to_cpu'
>>>    #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
>>>                                                      ^
>>>    In file included from drivers/clk/clk-k210.c:8:
>>>    In file included from include/linux/io.h:13:
>>>    In file included from arch/riscv/include/asm/io.h:149:
>>>    include/asm-generic/io.h:580:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>>>            outb(value, addr);
>>>            ^~~~~~~~~~~~~~~~~
>>>    arch/riscv/include/asm/io.h:59:68: note: expanded from macro 'outb'
>>>    #define outb(v,c)       ({ __io_pbw(); writeb_cpu((v),(void*)(PCI_IOBASE + (c))); __io_paw(); })
>>>                                                                  ~~~~~~~~~~ ^
>>>    arch/riscv/include/asm/mmio.h:91:52: note: expanded from macro 'writeb_cpu'
>>>    #define writeb_cpu(v, c)        ((void)__raw_writeb((v), (c)))
>>>                                                              ^
>>>    In file included from drivers/clk/clk-k210.c:8:
>>>    In file included from include/linux/io.h:13:
>>>    In file included from arch/riscv/include/asm/io.h:149:
>>>    include/asm-generic/io.h:588:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>>>            outw(value, addr);
>>>            ^~~~~~~~~~~~~~~~~
>>>    arch/riscv/include/asm/io.h:60:68: note: expanded from macro 'outw'
>>>    #define outw(v,c)       ({ __io_pbw(); writew_cpu((v),(void*)(PCI_IOBASE + (c))); __io_paw(); })
>>>                                                                  ~~~~~~~~~~ ^
>>>    arch/riscv/include/asm/mmio.h:92:76: note: expanded from macro 'writew_cpu'
>>>    #define writew_cpu(v, c)        ((void)__raw_writew((__force u16)cpu_to_le16(v), (c)))
>>>                                                                                      ^
>>>    In file included from drivers/clk/clk-k210.c:8:
>>>    In file included from include/linux/io.h:13:
>>>    In file included from arch/riscv/include/asm/io.h:149:
>>>    include/asm-generic/io.h:596:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>>>            outl(value, addr);
>>>            ^~~~~~~~~~~~~~~~~
>>>    arch/riscv/include/asm/io.h:61:68: note: expanded from macro 'outl'
>>>    #define outl(v,c)       ({ __io_pbw(); writel_cpu((v),(void*)(PCI_IOBASE + (c))); __io_paw(); })
>>>                                                                  ~~~~~~~~~~ ^
>>>    arch/riscv/include/asm/mmio.h:93:76: note: expanded from macro 'writel_cpu'
>>>    #define writel_cpu(v, c)        ((void)__raw_writel((__force u32)cpu_to_le32(v), (c)))
>>>                                                                                      ^
>>>    In file included from drivers/clk/clk-k210.c:8:
>>>    In file included from include/linux/io.h:13:
>>>    In file included from arch/riscv/include/asm/io.h:149:
>>>    include/asm-generic/io.h:1005:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>>>            return (port > MMIO_UPPER_LIMIT) ? NULL : PCI_IOBASE + port;
>>>                                                      ~~~~~~~~~~ ^
>>>>> drivers/clk/clk-k210.c:717:6: warning: variable 'reg' set but not used [-Wunused-but-set-variable]
>>>            u32 reg;
>>>                ^
>>>    8 warnings generated.
>>>
>>>
>>> vim +/reg +717 drivers/clk/clk-k210.c
>>>
>>>    710	
>>>    711	static int k210_clk_set_parent(struct clk_hw *hw, u8 index)
>>>    712	{
>>>    713		struct k210_clk *kclk = to_k210_clk(hw);
>>>    714		struct k210_sysclk *ksc = kclk->ksc;
>>>    715		struct k210_clk_cfg *cfg = &k210_clk_cfgs[kclk->id];
>>>    716		unsigned long flags;
>>>  > 717		u32 reg;
>>
>> Palmer,
>>
>> I do not think this driver is the real cause of this error. Did something change
>> recently with risc-v mmio readl()/writel() ?
> 
> I have no idea what's going on here.  When I try to re-build that config 
> I don't get any warnings or errors.  That said...
> 
>>>    718	
>>>    719		spin_lock_irqsave(&ksc->clk_lock, flags);
>>>    720		reg = readl(ksc->regs + cfg->mux_reg);
>>>    721		if (index)
>>>    722			reg |= BIT(cfg->mux_bit);
>>>    723		else
>>>    724			reg &= ~BIT(cfg->mux_bit);
>>>    725		spin_unlock_irqrestore(&ksc->clk_lock, flags);
> 
> Isn't reg unused here?  That's one of the warnings.

Yep. I just sent a patch to fix that. The writel() call to update the mux
register was missing (did not notice since the code basically use all default
parents and never change parents).

> The void* casting has been there for a while and looks like a real bug, 

Which (void *) cast are you talking about ? The one for the asm generic
definition of PCI_IOBASE ? That one is used in the case of NOMMU build since it
is not defined by arch/riscv for NOMMU builds.

> but asm-generic adopted our {in,out}{bwlq} implementation so I'm just 
> going to toss ours.  I'm not quite sure why the generic ones aren't 
> doing arithmetic on void*, but I'm not getting warnings.

I tried to compile the attached config with clang 12 and the compilation even
failed (on a frame buffer driver)... Have not tried W=1 build as Jisheng
mentioned. Anyway, if (void *) arithmetic is a problem with clang, I wonder how
anything can compile at all with it. That is used in a lot of places...

> 
>>>    726	
>>>    727		return 0;
>>>    728	}
>>>    729	
>>>
>>> ---
>>> 0-DAY CI Kernel Test Service, Intel Corporation
>>> https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
>>>
>>
>>
>> -- 
>> Damien Le Moal
>> Western Digital Research
>>
> 


-- 
Damien Le Moal
Western Digital Research

^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2021-06-14  2:08 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-06-03  9:34 drivers/clk/clk-k210.c:717:6: warning: variable 'reg' set but not used kernel test robot
2021-06-03 10:03 ` Damien Le Moal
2021-06-12  3:55   ` Palmer Dabbelt
2021-06-12 13:18     ` Jisheng Zhang
2021-06-14  2:08     ` Damien Le Moal

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